Apparatus for the treatment of yarns



April 19, 1960 RlcHMOND ETAL 2,932,935

APPARATUS FOR THE TREATMENT OF YARNS Filed June 10, 195'? to the axis of the jet and means being provided to United States Patent APPARATUS non Tim TREATMENT OF YARNS Alfred Richmond and Alexander Henderson Gentle, Spondon, near Derby, England, assignors to British Celanese Limited, a corporation of Great Britain Application June 10, 1957, Serial No. 664,695 Claims priority, application Great Britain June 22, 1956 9 Claims. (Cl. 57-34) This invention relates to the treatment of yarn and more particularly to apparatus for the production of voluminous yarn in which a continuous filament yarn is subjected to the action of a turbulent stream of fluid to produce a yarn in which the individual filaments or fibres are looped or curled at random intervals along their lengths giving the yarn, in some degree, the appearance and handle of a staple fibre yarn.

The invention is particularly concerned with a form of jet and jet assembly in which a yarn can be subjected to the action of the turbulent stream, and to which the yarn and a supply of fluid under pressure (generally compressed air) are fed. The yarn is drawn away from the jet and out of the fluid stream at a lower rate than that at which it is fed, the resulting overfeed permitting the formation of the loops and curls and preventing them from being pulled out as soon as they are formed. It has been found that a convenient form for such a jet comprises a body having therein an elongated chamber through which the yarn passes, and an outlet passage for the yarn in the form of a tube which extends rearwards for some distance into the elongated chamber so as to leave all round said tube a space extending forward of its rearwardly pointing tip, at which the yarn enters the tube, and means for supplying fluid under pressure into said chamber. According to one important feature of the invention, the compressed air or other fluid preferably enters the elongated chamber at a point of introduction beyond the rearwardly pointing tip of the outlet tube so that the air must return along the length of the chamber, against the direction of passage of the yarn, before leaving it with the yarn by way of the outlet tube. This arrangement appears to encourage turbulence of the fluid and to increase the number and regularity of the loops or curls formed along the lengths of the filaments. Furthermore, the jet can be readily threaded, without dismantling, by inserting the end of the yarn into the jet inlet until it reaches the elongated chamber and then turning on the fluid supply which carties the end into and through the outlet tube.

According to a further feature of the invention, the yarn outlet tube is sharpened to an acute annular edge at its tip, where the yarn enters it to leave the chamber. This feature also has the advantage of increasing the number and regularity of loops or curls, Whether the air is supplied to the chamber beyond (as is preferred), at or behind the point at which the yarn enters the outlet tube.

A still further feature of the present invention, applicable to jets of any kind, is the provision of a plate or like bafile which is rigidly fixed in relation to the jet, and against which the yarn and the fluid emerging from the jet are directed, the baffle being disposed at an angle lead the yarn away from the neighbourhood of the bathe in a direction out of that plane which is at right-angles to the baffle surface and contains the jet axis. This has the effect of improving the stability of the path of the yarn in the zone Where the yarn is drawn out of the fluid stream as the latter is deflected and somewhat broken up by the baflle, and where control of the yarn path is apt to be indeterminate.

The jet of the present invention may be of any convenient construction. In a preferred form, the jet comprises a T-piece of which the head of the T contains the elongated chamber and the yarn entry and outlet passages, while the single limb constitutes the compressed air inlet. The ends of the chamber in the head of the T are partly closed to receive separate tubes of small bore for the admission and withdrawal of the yarn. The yarn outlet tube extends for some distance into the chamber. The yarn inlet tube may extend into the chamber to meet the outlet tube where its tip may actually enter just inside the outlet opening or may fall short thereof leaving a small gap, or alternatively the tube may terminate flush with the entry end of the chamber. The head of the T-piece is preferably provided with means for locking in a desired axial position the yarn entry and exit tubes. This enables the axial positions of the tubes to be adjusted to suit the nature of the yarn employed as starting material and of the product desired therefrom and then to be locked in position. It has been found desirable for the yarn outlet tube not to extend outwards beyond the T-piece, but to fall a little short of the end thereof, so as to leave the end of the bore of the T-piece as a small cylindrical cavity beyond and forming a sudden enlargement of the bore of the outlet tube. Once the requisite positions of the inlet and outlet tubes have been found for one jet, it may be reproduced for other jets of the same form by means of suitable gauges.

The jet assembly of the invention is used in conjunction with suitable means for the feeding, drawing-off and collection of the yarn. Thus, the feed and take-up arrangernents for the yarn may comprise separate sets of feed rollers and draw-off rollers driven at different peripheral speeds to provide the required amount of overfeed to ensure that the loops and convolutions in the filaments are not pulled straight as they are drawn away from the jet assembly. Alternatively, a combined feed and draw-off unit may be used comprising a driven roller with two portions of different diameters, and nip rollers engaging with said portions, the yarn passing from the portion of larger diameter to the jet inlet and being withdrawn from the jet assembly by the portion of smaller diameter. From the draw-off rollers the yarn is preferably led to a down-twisting spindle where it is twisted so as to set the loops therein, though it is possible to lead the yarn to a winding device where it can be collected without the insertion of twist. In the latter case the continuous filament yarn may already have been twisted, the degree of twist having the effect of control ling the degree of loopiness and voluminosity obtained.

The jet and jet assembly according to the invention are suitable for the treatment of artificial continuous filament yarns in general, and particularly yarns of cellulose derivatives such as cellulose acetate and cellulose propionate, yarns of reconstituted cellulose such as viscose and yarns of synthetic polymers such as polyhexamethylene adipamide, polyaminocaproic acid, polyethylene terephthalate, polyacrylonitrile and polyaminotriaz oles.

By way of example, one form of yarn treating apparatus including a jet assembly in accordance with the invention ,will now be described in greater detail with reference to the accompanying drawing in which:

Figure l is a diagrammatic side elevation of the apparatus, and

of the .jet proper.

The apparatus comprises feed means in the form of a;

Y jet axis is not normal to the plane :fully explained below.

the rolls 3 and passes round-and over the upperfeed roll,

by which it is delivered vertically downwards to the inlet of the jet 8. I

The jet 8 itself, as shown in Figure 2, comprises a brass T-piece 9 with the double limb 11 about 2" in length arranged nearly vertically but pointing slightly forward and downwards, and the single limb 12 near horizontally. The upper end of the double limb 1.1 is longer than the lower end so that the single limb 12 is not quite symmetrically disposed. The double limb 13. is bored right through and the middle portion of the bore is enlarged to form an elongated chamber 13. Into the upper end of the bore is inserted a yarn inlet tube 14 whose lower end is flush with the upper end of the chamber and whose upper end is flush with the upper extremity of the double limb 11. The. yarn inlet tube is bored to a diameter of 0.8 mm, the upper end of the bore being conically flared or enlarged at E to facilitate threading. The inlet tube is held in position by means of a grub screw 16 passing radially through the wall of the T-piece. Into the lower end of the bore of the double limb 11 is inserted the yarn outlet tube 17. This has a bore of 2 mm. diameter and its upper end is conically sharpened to give an annular edge 38 of an angle of aboutZO". The sharpened upper end of the yarn outlet tube 17 extends well into the elongated chamber 23:, about three-quarters of the way from the lower to the upper end, and extends past the bore of the horizontal member 12 of the T. The lower end of the yarn outlet tube 17, lies within the lower end of the bore into which it is fitted so as to leave a small cylind'ricalcavity 19 between the outlet end of the tube 17 and the lower end of the double limb 11. The yarn outlet tube 17 is fixed in the jet, like the yarn inlet tube 14, by means of a grub screw 21. ing the lower end of the jet'8 is a collar 22, fixed by means of set-screw 23, from which extends a bracket 24 carrying at its lower end a baflie plate 25. The plate is set at an angle to the line of the jet axis, that is the of the plate, as more The front, orupper edge 26 of the plate is curved over through 180 at a radius of about A", and beyond the curve, fixed to the underside of the plate, is a pigtail guide 27 through which the yarn passes. the baffle plate 25 is set at an angle to (i.e. is not normal to) the axis of the jet 8; the angle between the plane of the bafile 25 and the plane containing both the axis of the jet and the guide 27 is about 60, while the angle between the-axis of the jet and the line of intersection of the said two planes is about 45 The baffle plate 25 is situated at a distance of about /2" from the end of the jet 8, 'measured'on the line of the jet axis. From the pigtail guide 27 the yarn passes through a second pair of corkrolls 28 driven with a peripheral speed less than that of the feed rollers 3 and supplying the yarn to the balloon guide 29 of a ring-spindle 31 or other twisting and winding'device by means of which the yarn 30 is twisted and wound into a package 32.

In operation the yarn 4 is threaded through the feed rollers 3 and its end is inserted downwards into the yarn inlet tube 14 until is reaches into the elongated chamber 13 within the jet 8. The compressed air supply is then turned on and the flow'of air through the limb12 of the T carries the yarn 4 through the outlet tube 17. The resulting voluminous yarn 30 is then threaded through the pigtail guide 27 and the nip rolls 28', the feedrollers 3 and nip rolls 28 are set in motion, and the yarn is Surround- 7 As mentioned above downward and forwardand steel-surfaced nip thrown-on to the ring-spindle 31. It is sometimes .possible to dispense altogether with the bafile plate 25, the pigtail guide 27 being placed just below and in front of the lower end of the jet, and the yarn 30 descending in a U-shaped loop under the influence of the stream of air emerging with it from the jet 3, before rising again to the pigtail guide from which it descends once more to the nip rolls 28.

As an example of the use of the apparatus, a cellulose acetate yarn of 300 denier, consisting of 52 filaments and having 0.45 turn per inch of Z twist is drawn from a cone '7 and supplied to the jet 8 at 13.3 metres per minute and is withdrawn by means of the output rolls 28 at 10 metres per minute. Air is supplied to the jet 3 at 10 pounds per square inch, being adjusted to give a pressure within the elongated chamber 13 (as measured by a manometer temporarily applied to the inlet 14 of the chamber) of about 7 pounds per'square inch. The rate of consumption of air is of the order of two-thirds of a cubic foot per minute. The resulting yarn is given a twist of l0'turns per inch, 2- twist. It has a denier of about 390 and exhibits numerous small loops or convolutions at random intervals along its length.

Having described our invention, what we desire to secure by Letters Patent is: v

1. A jet for the subjection of a yarn to the action of a turbulent fluid stream, said jet comprising a body having therein an elongated chamber with rearward and forward ends, an entry passage in the rearward end wall of the chamber by which the yarn passes into said chamher in the direction of the length of the chamber, an

7 outlet passage for the yarn in the forward end of the chamber, said passage being of larger diameter than the entry passage and being in the form of a tube which jextends rearwards for some distance into said chamber so as to leave all round said tube a space extending forward of its rearwardly pointing tip, and means for supplying fluid under pressure into said chamber at a point which lies forward of the rearwardly pointing tip of the outlet tube. V

2. Apparatus according to claim 1, wherein the yarn outlet tube is sharpened to an acute annular edge at its rearwardly pointing tip.

3. A jet according to claim 2, wherein the yarn entry passage is in a separate tube fitting into a bore in the jet body and terminating flush with the interior surface of the chamber within said body.

4. A jet according to claim 1, wherein the yarn outlet 7 tube is a separate member fitting into a bore in the jet body and falling short of the exit end of said bore so as to leave an enlarged cavity at the exit end of the tube. 5. A jet according to claim 1, wherein the yarn entry passage has a flared entrance and is thereafter of uniform diameter. V r V a 6. A vjet according to claim 1, wherein the'jetbody is in the form of a T-piece having a head portion and a tail portion of which the head portion of the T-piece contains the elongated chamber and the yarn exit and entry passages, and the tail portion contains the fluid inlet.

7. Add assembly for the subjection of a yarn to the action of a turbulent stream, said. assembly comprising a jet as claimed in claim '1, and a baffle rigidly fixed in relation to said jet beyond the exit end and at an angle to the axis thereof, and means for leading the yarn away from the neighbourhood of said baffie' in a direction out of the' plane which contains said axis and is at rightangles to the baffle surface.

8. An assembly according to claim 7, comprising a collar secured about the end of the jet body and carrying 9. Apparatus'suitable for the production of a voluminous yarn from a continuous filament yarn, said apparatus in claim 1, means for feeding a yarn into the inlet passage or said jet, andmeans for 5 6 drawing the yarn from the outlet passage of said jet at 2,194,565 Moss Mar. 26, 1940 a speed less than the yarn inlet speed. 2,302,790 Modigliani Nov. 24, 1942 2,773,282 Backer Dec. 11, 1956 References Cited in the file of this patent 2,783,609 Breen M 5, 1957 UNITED STATES PATENTS 5 2,807,862 Griset Oct. 1, 1957 2,100,588 Clans Nov. 30, 1937 

